1. Technological Field to Which the Invention Belongs
The invention of the present application relates to a substrate processing device suitable for use in the manufacture of display devices, such as liquid crystal displays.
2. Discussion of Related Art
In the manufacture of various display devices, such as liquid crystal displays and plasma displays, a process such as surface-processing must be administered on a plate-shaped material that forms the base of the device (hereinbelow referred to as the substrate). By way of example, in liquid crystal displays, a process to form a transparent electrode on the plate surface (surface that is not the peripheral surface) of the glass substrate is required.
The substrate processing device employed in processing of this kind comprises a chamber configured in such a way that it can be pumped out to a vacuum or a predetermined gas can be introduced to the inner space because the processing of the substrate is performed in a predetermined atmosphere. As different processes are continuously performed therein and the pressure must be gradually lowered from atmospheric pressure, the configuration that is adopted comprises a plurality of chambers.
Substrate processing devices of the prior art such as this may, in terms of the layout of the chambers, be broadly classified into two types. One is known as the inline-type and the other is known as the cluster tool-type.
FIG. 9 shows the schematic configuration of an inline-type device as a typical substrate processing device of the prior art. The inline-type device uses a configuration in which a plurality of chambers 2, 3, 11 and 12 are longitudinally-provided in a straight line. A carry system, which carries the substrate 9, is provided so as to penetrate the plurality of chambers 2, 3, 11 and 12. In addition, gate valves 10 are provided between the chambers 2, 3, 11 and 12.
The substrate 9 is carried in sequence through the chambers by the carry system in a state in which it is mounted on a tray 91 for processing. One of the plurality of chambers is a load-lock chamber 11 which opens to the atmosphere when the substrate 9 is carried in, and another chamber is a load-lock chamber 12 which opens to the atmosphere when the substrate 9 is carried out. The remaining chambers include chambers for processing (hereinbelow, processing chambers) 2. In addition, a chamber 3, provided between the processing chamber 2 and the load-lock chamber 11 or unload-lock chamber 12, constitutes a pressure-adjustment chamber. As there is a large pressure difference between the load-lock chamber 11 (or unload-lock chamber 12) and the processing chamber 2, the pressure adjustment chamber 3 maintains and adjusts the atmosphere to an interim pressure therebetween.
As shown in FIG. 9, the configuration of the carry system enables the movement of the tray 91, on which the substrate 9 is mounted, by the use of carry rollers 41. These carry rollers 41 constitute a pair of small disk-shaped members provided at both ends of a rotating shaft extending perpendicular with the direction of carry in the horizontal direction. The carry system is configured by the provision of, in a predetermined interval in the direction of carry, a large number of groups of rotating shafts and pairs of carry rollers 41. As is clear from FIG. 9, the substrate 9 is carried and processed horizontally.
On the other hand, FIG. 10 shows, as another example of a typical substrate processing device of the prior art, a schematic configuration of a cluster tool-type device. The cluster tool-type device uses a configuration in which, in the perimeter of a carry chamber 5 in which a transfer robot 42 is provided in the inner part, load-lock chambers 11 and a plurality of processing chambers 2 are provided. In the example shown in FIG. 10, two load-lock chambers 11 are provided. In addition, gate valves 10 are provided between the carry chamber 5, load-lock chambers 11, and the processing chambers 2.
The transfer robot 42 takes out the substrate 9 from one load-lock chamber 11 and carries it in sequence to the processing chambers 2. The transfer robot 42, following processing, returns the substrate 9 to the other load-lock chamber 11. It will be noted that, although the load-lock chamber 11 shown in FIG. 10 performs the unlock load chamber 12 function in the device shown in FIG. 9, the name “load-lock chamber” is used without alteration.
The transfer robot 42 is an articulated type robot. The substrate 9 is mounted and carried on the tip-end of the arm thereof. To carry the substrate 9 to a predetermined position, the transfer robot 42 performs arm extension and contraction, rotation, and a range of vertical movements. The substrate 9 is mounted and carried on the arm horizontally. In addition, the substrate 9 is also supported and processed horizontally within the processing chamber 2.
In substrate processing devices of this kind, at the heart of the demands for greater intricacy of the entire process and improvements to the productivity is the need for a large number of both different and identical processing steps to be able to be continuously performed. That is to say, due to an increased intricacy of the entire process, different processing steps must be continuously performed, and in order for productivity to be improved, identical processing steps must be broken up and performed at the same time. It will be noted that the term “continuously” used here refers to the execution of a next processing step without the substrate having been taken out into the atmosphere.
Because of a need to increase the number of processing steps in this way, the substrate processing devices of the prior art described above have the following problems.
First, in inline-type substrate processing devices, when the number of processing chambers is increased in order to increase the number of processing steps, the length of the device in the direction of the tray line is lengthened by that amount. In inline-type devices, because the substrate is carried in from one side of the device and is carried out from the other side, problems of workability and efficiency arise when the length of the device is increased and the carry-in position and the collection position of the substrate are separated further. In addition, a problem arises in that it is difficult for devices that are lengthy to be assembled in existing production lines.
On the other hand, in cluster tool-type devices, if an attempt is made to increase the number of processing chambers, the sides of the center carry chamber must be enlarged. There are drawbacks accompanying this in that the cross-section of the carry chamber is larger and the occupied area of the device as a whole is larger. As the carry chamber is a section that does not directly contribute to productivity, an increase in size of this section is undesirable. In addition, when the carry chamber is enlarged, there are problems in that the scale of the pump system for pumping out the inner space is larger and more expensive. Furthermore, when the carry chamber is enlarged, the operation range required of the carry robot for carrying the substrate to the chambers increases. As a result, the scale of the transfer robot is larger and more expensive and, as a result of a lengthening of the arm of the transfer robot, problems in flexibility of the arm and reduction of carry precision arise.